화학공학소재연구정보센터
Journal of Vacuum Science & Technology B, Vol.25, No.6, 2317-2320, 2007
Ultrastiff stage for imprint lithography
The high-resolution capabilities of imprinting and step and flash make these techniques strong contenders for the next generation lithography. Unfortunately, alignment remains an area of concern for imprinting because it must be completed before the template is moved into contact with the wafer. The large forces on the template during the process, even for step and flash, place additional demands on the stiffness as well as the reproducibility of the template stage. A prototype flexure stage has been developed to meet these demands. A compressive load, slightly below the Euler limit, is used to produce relatively free motion in the vertical direction while maintaining extremely high horizontal stiffness. In addition, the horizontal stage position is viewed by an optical system based on a microscope objective with a central stop. With it, the horizontal position of a diffraction grating fixed to the stage has been measured to a few nanometers, over a vertical range of several hundred microns. Consequently, not only does the high transverse stiffness of the stage minimize unwanted horizontal motions but also any that occur are measured over the entire required range of motion. (c) 2007 American Vacuum Society.